1mtx1

What is the stock plug for a sh.18 motor,medium or hot? I have 2 spair hot plugs. Knock on wood I never really had a plug fail during my 5 tank brake in method even in to my 6 tank in which I start my tune . I was thinking brake the motor in and with the stock plug which I think is medium then switch to a hot plug for my 6th. Or maybe can i just roll with the stock plug all the way up to when I dial the motor in. (6th tank7th) gonna use O'Donnell 20% fuel an outside temperature been 50's-70ish an getting colder . I have broke in motors in 35-40deg I really wanna get it done on a 60 deg day